Using datasets as business objects

I have to use datasets as business objects in an old .net 2.0 project, but a business object without business logic isn't that useful so I added some logic by using partial classes.
Examples of logic could be checking that the row is valid when a row is modified, like below, also you can add some methods to the database instance for convenience.

//Use the partial class of the dataset
partial class CustomerEnquiryDataset
   {
       //Dataset method available for the dataset instance
       public string GetFirstEnquiryTitleString()
       {
     //Ugly, but an example of a dataset instance method...
     return Tables["TblCustomerEnquiry"].Rows[0]["Title"].ToString();
       }

       //Create partial class of the dataset table to override EndInit()
       public partial class TblCustomerEnquiryDataTable
       {
           public override void EndInit()
           {
               base.EndInit();
  //Take action if a datarow changes in the TblCustomerEnquiryDataTable
               this.RowChanged += new System.Data.DataRowChangeEventHandler(TblCustomerEnquiryDataTable_RowChanged);
           }

           private void TblCustomerEnquiryDataTable_RowChanged(object sender, System.Data.DataRowChangeEventArgs e)
           {
               TblCustomerEnquiryRow myOrderRow = (TblCustomerEnquiryRow) e.Row;
               if (myOrderRow.Title.Length < 1)  
               {    throw new System.Exception("The title you entered is empty");
   }
   }  
         
      }
 }